/*
 * TeleStax, Open Source Cloud Communications  Copyright 2012.
 * and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.mobicents.protocols.ss7.cap.primitives;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.mobicents.protocols.asn.AsnException;
import org.mobicents.protocols.asn.AsnInputStream;
import org.mobicents.protocols.asn.AsnOutputStream;
import org.mobicents.protocols.asn.Tag;
import org.mobicents.protocols.ss7.cap.api.CAPException;
import org.mobicents.protocols.ss7.cap.api.CAPParsingComponentException;
import org.mobicents.protocols.ss7.cap.api.CAPParsingComponentExceptionReason;

/**
 * 
 * @author amit bhayani
 * @author sergey vetyutnev
 * 
 */
public abstract class TbcdString implements CAPAsnPrimitive {

	protected static int DIGIT_1_MASK = 0x0F;
	protected static int DIGIT_2_MASK = 0xF0;

	protected String data;

	protected int minLength;
	protected int maxLength;
	protected String _PrimitiveName;

	public TbcdString(int minLength, int maxLength, String _PrimitiveName) {
		this.minLength = minLength;
		this.maxLength = maxLength;
		this._PrimitiveName = _PrimitiveName;
	}

	public TbcdString(int minLength, int maxLength, String _PrimitiveName, String data) {
		this(minLength, maxLength, _PrimitiveName);

		this.data = data;
	}

	public int getTag() throws CAPException {
		return Tag.STRING_OCTET;
	}

	public int getTagClass() {
		return Tag.CLASS_UNIVERSAL;
	}

	public boolean getIsPrimitive() {
		return true;
	}

	@Override
	public void decodeAll(AsnInputStream ansIS) throws CAPParsingComponentException {

		try {
			int length = ansIS.readLength();
			this._decode(ansIS, length);
		} catch (IOException e) {
			throw new CAPParsingComponentException("IOException when decoding " + _PrimitiveName + ": " + e.getMessage(), e,
					CAPParsingComponentExceptionReason.MistypedParameter);
		}
	}

	public void decodeData(AsnInputStream ansIS, int length) throws CAPParsingComponentException {

		try {
			this._decode(ansIS, length);
		} catch (IOException e) {
			throw new CAPParsingComponentException("IOException when decoding " + _PrimitiveName + ": " + e.getMessage(), e,
					CAPParsingComponentExceptionReason.MistypedParameter);
		}
	}

	protected void _decode(AsnInputStream ansIS, int length) throws CAPParsingComponentException, IOException {

		if (!ansIS.isTagPrimitive())
			throw new CAPParsingComponentException("Error decoding " + _PrimitiveName + ": field must be primitive",
					CAPParsingComponentExceptionReason.MistypedParameter);
		
		if (length < this.minLength || length > this.maxLength)
			throw new CAPParsingComponentException("Error decoding " + _PrimitiveName + ": the field must contain from " + this.minLength + " to "
					+ this.maxLength + " octets. Contains: " + length, CAPParsingComponentExceptionReason.MistypedParameter);

		try {
			this.data = decodeString(ansIS, length);
		} catch (IOException e) {
			throw new CAPParsingComponentException("IOException when decoding IMSI: " + e.getMessage(), e,
					CAPParsingComponentExceptionReason.MistypedParameter);
		}
	}
	
	public void encodeAll(AsnOutputStream asnOs) throws CAPException {
		
		this.encodeAll(asnOs, this.getTagClass(), this.getTag());
	}

	public void encodeAll(AsnOutputStream asnOs, int tagClass, int tag) throws CAPException {
		
		try {
			asnOs.writeTag(tagClass, this.getIsPrimitive(), tag);
			int pos = asnOs.StartContentDefiniteLength();
			this.encodeData(asnOs);
			asnOs.FinalizeContent(pos);
		} catch (AsnException e) {
			throw new CAPException("AsnException when encoding " + _PrimitiveName + ": " + e.getMessage(), e);
		}
	}

	public void encodeData(AsnOutputStream asnOs) throws CAPException {

		if (this.data == null)
			throw new CAPException("Error while encoding the " + _PrimitiveName + ": data is not defined");

		encodeString(asnOs, this.data);
	}

	public static String decodeString(InputStream ansIS, int length) throws IOException, CAPParsingComponentException {
		StringBuilder s = new StringBuilder();
		for (int i1 = 0; i1 < length; i1++) {
			int b = ansIS.read();

			int digit1 = (b & DIGIT_1_MASK);
			if (digit1 == 15) {
				// this is mask
			} else {
				s.append(decodeNumber(digit1));
			}

			int digit2 = ((b & DIGIT_2_MASK) >> 4);
			if (digit2 == 15) {
				// this is mask
			} else {
				s.append(decodeNumber(digit2));
			}
		}

		return s.toString();
	}

	public static void encodeString(OutputStream asnOs, String data) throws CAPException {
		char[] chars = data.toCharArray();
		for (int i = 0; i < chars.length; i = i + 2) {
			char a = chars[i];

			int digit1 = encodeNumber(a);
			int digit2;
			if ((i + 1) == chars.length) {
				// add the filler instead
				digit2 = 15;
			} else {
				char b = chars[i + 1];
				digit2 = encodeNumber(b);
			}

			int digit = (digit2 << 4) | digit1;

			try {
				asnOs.write(digit);
			} catch (IOException e) {
				throw new CAPException("Error when encoding TbcdString: " + e.getMessage(), e);
			}
		}
		
	}
	
	protected static int encodeNumber(char c) throws CAPException {
		switch (c) {
		case '0':
			return 0;
		case '1':
			return 1;
		case '2':
			return 2;
		case '3':
			return 3;
		case '4':
			return 4;
		case '5':
			return 5;
		case '6':
			return 6;
		case '7':
			return 7;
		case '8':
			return 8;
		case '9':
			return 9;
		case '*':
			return 10;
		case '#':
			return 11;
		case 'a':
			return 12;
		case 'b':
			return 13;
		case 'c':
			return 14;
		default:
			throw new CAPException(
					"char should be between 0 - 9, *, #, a, b, c for Telephony Binary Coded Decimal String. Received "
							+ c);

		}
	}

	protected static char decodeNumber(int i) throws CAPParsingComponentException {
		switch (i) {
		case 0:
			return '0';
		case 1:
			return '1';
		case 2:
			return '2';
		case 3:
			return '3';
		case 4:
			return '4';
		case 5:
			return '5';
		case 6:
			return '6';
		case 7:
			return '7';
		case 8:
			return '8';
		case 9:
			return '9';
		case 10:
			return '*';
		case 11:
			return '#';
		case 12:
			return 'a';
		case 13:
			return 'b';
		case 14:
			return 'c';
			// case 15:
			// return 'd';
		default:
			throw new CAPParsingComponentException(
					"Integer should be between 0 - 15 for Telephony Binary Coded Decimal String. Received "
							+ i, CAPParsingComponentExceptionReason.MistypedParameter);

		}
	}
	
	@Override
	public String toString() {
		return _PrimitiveName + " [" + this.data + "]";
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((data == null) ? 0 : data.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		TbcdString other = (TbcdString) obj;
		if (data == null) {
			if (other.data != null)
				return false;
		} else if (!data.equals(other.data))
			return false;
		return true;
	}
}
